Can you drown a fish? (idea)

Betta splendens, commonly known as Saimese fighting fish, rely heavily on their labyrinth organs for oxygen and as such can easily be drowned in oxygen-poor water if they are prevented from surfacing to gulp air. I once had a betta who got trapped under a plant in his tank and subsequently drowned as he was unable to free himself and reach the surface. Even though there was a bubble stone in his tank, he was unable to get enough oxygen through the sole use of his gills.